3.4 Learning curve in LBBAP with SDL procedures
To eliminate bias, analyses were performed on patients who underwent the same procedure by a single operator. In 65 patients who underwent conventional RVP, the mean fluoroscopy and procedural time were 5.6 ± 3.2 and 42.7 ± 15.5 minutes, respectively. Of the 50 patients who underwent LBBAP, the mean fluoroscopy and procedural times across all procedures were 15.1 ± 13.5 and 59.9 ± 24.8 minutes, respectively (Table 3). The fluoroscopy and procedure times for LBBAP were modeled as cubic spline functions, and the curve showed that both fluoroscopy and procedure time decreased with operator experience (Figure 2). To confirm the plateau phase of the procedure time, we differentiated the cubic spline curve with respect to the procedure time to find the point where the slope was zero (Supplementary Figure S5). In this study, the plateau phase of the procedure time for LBBAP began in the 24th case. We compared the difference in procedure time between conventional RVP and LBBAP in the two phases based on the 24th case where the treatment time plateau was performed (before plateau phase ≤ 24th case, and after plateau phase > 24th case) (Figure 3). After the plateau was achieved during the LBBAP procedure, the median time difference between the two methods was confirmed to be 16 min (Table 3).